Clinical Course of Hypertrophic Pulmonary Osteoarthropathy in a Patient Receiving Immune Checkpoint Inhibitor Therapy

Hypertrophic pulmonary osteoarthropathy (HPOA) is a well-known paraneoplastic syndrome associated with lung cancer, and some have hypothesized that its pathophysiology is immune-mediated. However, the clinical course of symptoms from this syndrome during treatment with immune checkpoint inhibitors (ICIs) has not previously been described, and effective treatments for pain secondary to HPOA have not been fully elucidated. We present the case of a patient who was diagnosed with HPOA involving the bilateral distal femurs causing severe pain and subsequently found to have adenocarcinoma of the lung. We describe changes in her symptoms during multiple lines of treatment, including ICIs, and we discuss effective strategies for pain management for this condition. The patient's pain improved with regression of her tumor burden after treatment with chemotherapy, combined modality chemotherapy-radiation, and immune checkpoint inhibition. Importantly, her pain did not flare even temporarily with administration of ICIs. Severe episodes of pain prior to initiating treatment and during periods of cancer progression were managed effectively with opioids, dexamethasone, and hydroxychloroquine, the use of which has not been previously described for this condition. This case provides evidence that ICIs do not worsen symptoms of HPOA, despite their stimulation of an anti-tumor immune response, supporting their use in patients with this condition. It also provides support for the possible efficacy of hydroxychloroquine for treatment of pain secondary to HPOA in conjunction with other therapies. (C) 2020 Elsevier Inc. All rights reserved.